Adhesive sheets comprising an adhesive layer consisting of a foamable thermosetting adhesive composition for which the volume expands by heating at or above a prescribed temperature and the adhesive force increases as the curing reaction progresses are favorably used, for example, in void filling applications. As for this type of adhesive sheet, a thermally foamable sheet composition consisting of a foamable thermosetting resin composition essentially comprising a resin component containing an epoxy resin that is in a liquid or semi-solid state at room temperature and a thermal foaming agent containing an amine carbonate salt, is known (Patent Document 1).